July 13, 2000
The Honorable Michael Crapo
Subcommittee on Fisheries, Wildlife, and Drinking Water
Environment and Public Works Committee
United States Senate
Washington, D.C. 20510

RE: "Safe Drinking Water Act", June 29, 2000.

Dear Mr. Chairman:

The American Dental Association (ADA) has endorsed fluoridation of community water systems for 50 years as a safe and effective way to prevent tooth decay. Fluoride is nature's cavity fighter, occurring naturally in the earth's crust, in combination with other minerals in rocks and soil. Small amounts of fluoride occur naturally in all foods and beverages. Water fluoridation is the process of adjusting the natural level of fluoride to a concentration sufficient to protect against tooth decay, a range of from 0.7 parts per million (ppm) to 1.2 ppm.

Thanks in large part to community water fluoridation, half of all children ages 5 to 17 have never had a cavity in their permanent teeth. According to the April 2000 Journal of Dental Research, the use of fluorides in the past 40 years has been the primary factor in saving some $40 billion in oral health care costs in the United States.

Just last month, Surgeon General David Satcher wrote in his report, Oral Health Care in America, "Community water fluoridation is safe and effective in preventing dental caries in both children and adults. Water fluoridation benefits all residents served by community water supplies regardless of their social or economic status."

Revised national health objectives in Healthy People 2010 again include objectives to improve the nation's oral health. Oral Health Objective 9 states that at least 75% of the population should be receiving the benefits of optimally fluoridated water by the year 2010. According to the most recent Centers for Disease Control and Prevention (CDC) Fluoridation Census, only 62% of the population served by public water systems has access to fluoridated water.

After 50 years of research and practical experience, the preponderance of scientific evidence indicates that fluoridation of community water supplies is both safe and effective. Methods and populations differ, but studies show that water fluoridation can reduce decay in baby teeth by as much as 60% and can reduce tooth decay in permanent teeth by nearly 35%.

Even before the first community fluoridation program began in 1945, epidemiological data from the 1930s and 1940s revealed lower decay rates in children consuming naturally occurring fluoridated water compared to children consuming fluoride-deficient water.

Since that time, innumerable studies have been conducted to demonstrate the safety and/or effectiveness of water fluoridation. Three outstanding reviews of community water fluoridation are:

  • Newbrun E. Effectiveness of water fluoridation. J Public Health Dent 1989;49(5):279-89. (Results of 113 studies in 23 countries were analyzed.)
  • Ripa LW. A half-century of community water fluoridation in the United States: review and commentary. J Public Health Dent 1993;53(1):17-44. (Analysis of fifty-year history of community water fluoridation.)
  • Murray JJ. Efficacy of preventive agents for dental caries. Caries Res 1993;27(Suppl 1):2-8. (Review of studies conducted from 1976 through 1987.)
Numerous large-scale epidemiological studies of water fluoridation have been conducted, making fluoridation one of the most widely studied public health measures. Because these large investigations have been consistently validated, water fluoridation is not as frequently studied as in past decades. Water fluoridation is a perfect example of how well designed studies stand the test of time and scientific scrutiny. Studies included in the review articles listed continue to be referenced today and have become "classics" in the public health field.

Many well-documented studies have compared the decay rates of children before and after fluoridation in the same community, as well as with children in naturally fluoridated and/or nonfluoridated communities. Because of the high geographic mobility of our populations and the widespread use of fluoride toothpastes, supplements and other topical agents, such comparisons are becoming more difficult to conduct.

Although other forms of fluoride are available, persons in nonfluoridated communities continue to demonstrate higher dental decay rates than their counterparts in communities with water fluoridation as determined in the following studies:

  • Brunelle JA, Carlos JP. Recent trends in dental caries in U.S. children and the effect of water fluoridation. J Dent Res 1990;69(Spec Iss):723-7. (Review of 1987 survey of 40,000 school children compared to survey in 1979-80.)
  • Horowitz HS. The effectiveness of community water fluoridation in the United States. J Public Health Dent 1996 Spec Iss;56(5):253-8. (Review of fifty years of water fluoridation.)
  • Selwitz RH, Nowjack-Raymer RE, Kingman A, Driscoll WS. Dental caries and dental fluorosis among schoolchildren who were lifelong residents of communities having either low or optimal levels of fluoride in drinking water. J Public Health Dent 1998;58(1):28-35. (Review of tooth decay experience between children who were lifelong residents of optimally fluoridated communities versus those who were lifelong residents of communities having low fluoride levels in drinking water.)
The safety and/or effectiveness of community water fluoridation have been examined not only in communities within the US, but also in other communities worldwide. Below are several international studies of community water fluoridation:
  • Fluoride, teeth and health. Royal College of Physicians. Pitman Medical, London;1976. (There is no evidence of a relationship between water fluoridation and congenital malformations, thyroid disorders, cancers or allergies.)
  • Knox EG. Fluoridation of water and cancer: a review of the epidemiological evidence. Report of the Working Party. London: Her Majesty’s Stationary Office;1985. (Neither fluoride occurring naturally in water, nor fluoride added to water supplies, is capable of inducing cancer, or of increasing the mortality from cancer.)
  • Spencer AJ, Slade GD, Davies M. Water fluoridation in Australia. Comm Dent Health 1996;13(Suppl 2):27-37. (Water fluoridation is the most effective and socially equitable means of achieving community wide reductions in dental decay.)
  • World Health Organization. Fluorides and oral health. Report of a WHO Expert Committee on Oral Health Status and Fluoride Use. WHO Technical Report Series 846. Geneva;1994. (Water fluoridation is the most effective method of reaching an entire population so that all social classes benefit without the need for active participation on the part of individuals. It is essential that water fluoridation have the support of the leading health authorities and of the government.)
Mr. Chairman, community water fluoridation plays an important role in the health of infants and toddlers. Early childhood caries (ECC) is a serious socio-behavioral and dental problem that afflicts infants and toddlers in many communities and populations in the United States and other countries. The condition reaches epidemic proportions in low-income and Native American communities in the US. Known also as baby bottle tooth decay or nursing bottle mouth, the condition is characterized by severe decay, especially in the upper front teeth, which can result in tooth loss in infants and toddlers. Water fluoridation has been identified as the most highly recommended preventive strategy for early childhood caries.
  • Ismail AI. Prevention of early childhood caries. Community Dent Oral Epidemiol 1998;26(Suppl 1):49-61. (Water fluoridation provides the only means of ECC prevention that does not require a dental visit or parental motivation.)
From time to time, the safety and effectiveness of water fluoridation has been questioned. None of these charges has ever been substantiated by generally accepted science. It is important to review information about fluoridation with a critical eye.

Recently, extensive investigative reports found no scientific evidence that exposure to fluoride at the levels found in optimally fluoridated water presents any risk for the development of any disease process.

There have been claims that exposure to fluoride presents a neurotoxic (harmful or damaging to nerve tissue) risk or lowered intelligence. Such claims are based on a 1995 study (Mullenix PJ, Denbesten PK, Schunior A, Kernan WJ. Neurotoxicity of sodium fluoride in rats. Neurotoxicol Teratol 1995;17(2):169-77) in which rats were fed fluoride at levels up to 125 times greater than that found in optimally fluoridated water. The study attempted to demonstrate that rats fed extremely high levels of fluoride (75 ppm to 125 ppm in drinking water) showed behavior-specific changes related to cognitive deficits. These amounts are far in excess of the U.S. Public Health Service recommended fluoride levels of 0.7 to 1.2 ppm in water systems.

In addition, the experiment also studied the offspring of rats who were injected two to three times a day with fluoride during their pregnancies in an effort to show that prenatal exposure resulted in hyperactivity in male offspring. Independent scientific review of this finding did not support the conclusions made by the authors and discounts the potential of sodium fluoride as a potential neurotoxicant. (Ross JF, Daston GP. Neurotoxicology and Teratology 1995;17(6):685-6.) (Whitford GM. The metabolism and toxicity of fluoride, 2nd rev. ed. Monographs in oral science, Vol. 16. Basel, Switzerland: Karger;1996.)

Other studies attempted to link fluoride exposure to direct effects of the brain. One such 1998 study raised concerns about potential relationships between aluminum-fluoride and sodium-fluoride and Alzheimer's disease. (Varner JA, Jensen KF, Horvath W, Isaacson RL. Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity. Brain Res 1998;784:284-98.) Upon further review by other scientists, the study was found to contain major flaws in the experimental design, making it impossible for any definitive conclusions to be drawn. (American Dental Association, Health Media Watch: Study linking fluoride and Alzheimer’s under scrutiny. J Am Dent Assoc 1998;129:1216-8). The study also conflicts with the position of the Alzheimer's Disease Foundation, which states that there is little evidence to suggest that aluminum has a causative role in the disease.

Another study related to the comparison of fluoridated versus non-fluoridated communities in upstate New York (Schlesinger ER, Overton DE, Chase HC, Cantwell KT. Newburgh-Kingston caries-fluorine study XIII: pediatric findings after ten years. J Am Dent Assoc 1956;52:296-306). The original study noted a five-month difference in the average age of menarche between girls from the two cities, which the authors indicated as "not statistically significant."

One risk that has been attributed to water fluoridation is the possible formation of very mild dental fluorosis on permanent teeth in about 13% of children. Dental fluorosis is not a health effect; it is a cosmetic effect usually unnoticeable by untrained examiners. Mild dental fluorosis is characterized by nearly imperceptible white flecks in the enamel of permanent teeth. The risk of dental fluorosis can be greatly reduced by simple steps and without denying children the benefits of water fluoridation.

In 1997, the Food and Nutrition Board of the Institute of Medicine developed a comprehensive set of reference values for dietary nutrient intakes. These new reference values, the Dietary Reference Intakes (DRI), replace the Recommended Dietary Allowances (RDA) that had been set by the National Academy of Sciences since 1941. The new values present nutrient requirements to optimize health and, for the first time, set maximum-level guidelines to reduce the risk of adverse effects from excessive consumption of a nutrient. Along with calcium, phosphorous, magnesium and vitamin D, DRIs for fluoride were established because of its proven effect on tooth decay.

Mr. Chairman, the ADA's policies regarding community water fluoridation are based on generally accepted scientific knowledge. This body of knowledge is based on the efforts of nationally recognized scientists who have conducted research using the scientific method, have drawn appropriate balanced conclusions based on their research findings and have published their results in peer-reviewed professional journals that are widely held or circulated. Confirmation of scientific findings also reinforces the validity of existing studies.

With the advent of the Information Age, a new type of "pseudo-scientific literature" has developed. The public often sees scientific and technical information quoted in the press, printed in a letter to the editor or distributed via an Internet Web page. Often the public accepts such information as true simply because it is in print. Yet the information is not always based on research conducted according to the scientific method, and the conclusions drawn from research are not always scientifically justifiable. In the case of water fluoridation, an abundance of misinformation has been circulated. Therefore, scientific information from all print and electronic sources must be critically reviewed before conclusions can be drawn.

We have attached a copy of the ADA' s recent publication Fluoridation Facts to provide additional information concerning the safety and effectiveness of community water fluoridation. Nearly 100 national and international organizations recognize the public health benefits of fluoridation for preventing dental decay. We would appreciate your including this along with our letter in the hearing record.

Richard F. Mascola, D.D.S.
John S. Zapp, D.D.S.
Executive Director